(CNN) -- That a cell phone can keep people perpetually connected and findable is no mystery. But such an always-on gadget can also be a valuable tool to help someone disappear.

Frank Ahearn is a privacy expert who, for the last nine years, has consulted clients on how to go into hiding.

Victims of violent crime or abusive partners seek out Ahearn for help. Women looking to escape arranged marriages, a still-prevalent phenomenon in some cultures, also have provided a steady flow of clients, he said.

Ahearn generally provides stalker victims with free advice. He calls it "Ahearn's witness protection program." But skittish business travelers can pay between $12,000 and $25,000 for Ahearn's services.

Ninety-nine percent of the 500 to 1,000 people who visit his website every day get there by typing into Google or another search engine: "how to disappear."

With the rise of cell phones and smartphones, Ahearn has learned that you don't need to go off the grid in order to hide out.

"The cell phone has been a godsend," he said on the phone from New York recently. "You can use it to your advantage."

Ahearn offers some tips to help conceal yourself.

For one, use a prepaid cell phone. These are more difficult to track, Ahearn said. And they can usually be bought with cash or a prepaid credit card, eliminating a paper trail.

Many cell phones and most smartphones include a GPS chip that can be tapped into by the cell carrier or shrewd hacker for location-tracking purposes. Some phones sold overseas don't include that chip, Ahearn said. There are shops in the U.S. that will remove GPS chips from a phone, he added.

Also to avoid having your location pinned, Ahearn suggests leaving your main cell phone at home and forwarding those calls to another number. These Remote Call Forwarding numbers can be obtained for free from a service such as Google Voice.

"The great part about this is we can have different numbers," Ahearn wrote in an e-mail. For example, you'd have "one for work, for girlfriends, credit card companies and we can simply hide behind the virtual numbers."

While phones can be helpful for people trying to disappear, they can also make it simple to find someone who doesn't know the tricks of hiding.

Ahearn knows. He started his career as a skip tracer, locating people for a bounty.

Many of the stunts he used, such as persuading telecom companies to let him access phone records, are now illegal. But scouring social-network profiles -- Facebook, Twitter and, perhaps the granddaddy of all finders' tools, Foursquare -- is legit.

"Technology is like a double-edged sword," Ahearn wrote. "You can use technology to find information on people, from their social-networking accounts to reverse directories to miscellaneous database searches online."

But social networks can also be used to the hider's advantage.

"You can use the social media as disinformation," Ahearn advised. "You can start posting stuff, pictures of your supposed trip to Utah, tweet people telling them you're looking for a place to live in Utah" when in fact you are somewhere else.

That sort of misdirection was a crucial tactic for Evan Ratliff, who tried to vanish off the grid and from readers' prying eyes for a Wired magazine article. Another clever trick is to ask friends and family to post bogus information about your whereabouts, Ahearn added.

One final piece of advice: No matter how good that neighborhood Mexican restaurant is, refrain from "checking in" there via your phone. Your Foursquare friends can find their own dining recommendations.